Safety sole for footwear



July 13, 1954 E. A. SPRIGG 2,683,317

SAFETY SOLE FOR FOOTWEAR Filed June 28, 1950 2 Sheets-Sheet l INVENTOR.

ATTORNEYS y 13, 1954 E. A. SPRIGG 2,683,317

SAFETY SOLE FOR FOOTWEAR Filed June 28, 1950 2 Sheets-Sheet 2 IN VEN TOR.

ATTORNEYS Patented July 13, 1954 UNITED s'rA'rss PATENT OFFICE SAFETY SOLE FOR FOOTWEAR Edward A. Sprigg, East Orange; N. J., assignmto David E. Crooker, Ontonagon, Mich., and Lloyd Felker, Marshfield, Wis.

Application June 28, 1950, Serial No. 170,800

4- Claims. 1

This invention relates to improvements in the art of manufacturing safety shoes;

This invention relates to shoes of the type worn by workmen, campers, mountainers, troops, etc. who must have secure footing in all kinds of weather and, more particularly, to safety soles for such shoes which are so designed as to afford sure footing and to prevent accidents and injuries resulting from the wearer's slipping on ice or other insecure ground.

Many types of workmans shoes embodying safety soles have been designed in the past including of course the famous hob-nails which are widely used by lumbermen and others who must work in'slippery, insecure locations. The disadvantage of the hob-nail type of shoes arises from the fact that the hob-nails protrude from the soles at all times and constantly are subjected to wear whether or not they are necessary for the safety of the wearer. For example, if a pair of bob-nail shoes is worn on a stone, cement, or other hard, abrasive surface, the hob-nails are rapidly worn down until their usefulness is destroyed.

It is the principal object of this invention to provide a safety sole for a shoe which sole is an improvement upon the structure shown and described in Crooker Patent No. 2,557,946, issued June 26, 1951. V 7

It is another object of this invention to provide a safety sole for a shoe, embodying metallic gripping elements which withdraw when not in use and which protrude into gripping position immediately upon excessive pressure being applied upon the soles of the shoes resulting when slippery conditions are encountered.

A further object of the present invention is to provide adevice of the class described wherein the sole is formed with transversely extending safety elements of substantially equal length.

which are staggered transversely with respect to one another whereby the sole can be substantially fully covered throughout its width with safety elementswithout requiring safety elements of more than one length.

A more specific object of the invention is void of safety elements.

.,A further object of the invention isto provide a shoe construction including ribs in which safety'elements are imbedded, wherein safety elements of standard length may be efficiently employed both in the sole portion and in the heel portion.

A further object of the invention is to provide animproved method of manufacturing safety shoes containing elongated safety elements.

These general objects and more specific objects and advantages will'beclearly understood from the description which follows and from the drawings in which:

Fig. I is a plan view of a shoe the invention;

Fig. 11 is a vertical sectional view taken substantially on theline II--II of Fig. I and showing the transverse profile of the ribs on the heel of the shoe;

Fig. III is a side elevation of a shoe equipped with a safety sole embodying the invention;

Fig. IV is a fragmentary view in elevation of one oftheribs in which the safety grapsing device is embedded and showing the rib and safety device before use.

Figure V is, a view similar to Figure IV but showing the appearance of the rib after a slight amount of use;

' Figure-VI is a View similar to Figures IV and V but showing the rib and the safety device after considerable use;

Figure VII is a transverse sectional view of the rib illustrated in Figure IV;

Fig-ure'VIiI is a view similar to Figure VII but of the rib in the condition illustrated in Figure V;

Figure IX is a View similar to Figures VII and VIII but of the rib in the condition illustrated in Figure VI;

Figure X is a fragmentary plan view of one of the ribs in which the safety device is embedded and showingit before use as also is illustrated in Figures IV and VII;

Figure X1 is a plan view of the rib in the condition illustrated in Figures V and VIII;

Figure m1 is a plan view of the rib in the sole embodying condition illustrated in Figures VI and IX;

Figure XIII is a greatly enlarged view in elevation of one of the safety devices which is embedded in each of the gripping ribs constituting th safety elements of a safety sole embodying the invention; and

Figure XIV is an end view of the element shown in Figure XIII.

A safety sole embodying the invention consistsof a base portion l of rubber or the equivalentcompositioninaterial which extends-through 3 out the surface of the sole and/or heel of the shoe 2 and by means of which the sole is cemented, sewed, tacked or otherwise secured to the underside of the shoe 2. In Figure II the shoe is illustrated as having a separate heel 3 to which is affixed a separate base portion 4, although in some forms of shoes the same base portion will be continuous from the sole to the heel.

Molded integrally with the base portions l and 4, or otherwise formed to be retained on the shoe by the base portions I and 4, are a plurality of generally parallel, transverse raised ribs 5, E and I. Each of the ribs 5 contains one of the safety elements which embodies the invention. This safety element consists of a coil 8 (see Figure XIII) preferably formed of a wearresistant, resilient metal such as steel. Each of the ribs 5 is formed or molded from a wearresistant material such as synthetic or natural rubber and does not contain one of the safety elements, the coils 3. 'The purpose of the ribs 6 is merely to fill in this undersurface of the sole so that the raised ribs will generally cover the entire surface of the sole. By so designing the sole that it is made up of groups of the safety element containing ribs 5 and the shorter ribs 6, the undersurface of the sole can be more fully covered with the raised ribs and the safety elements staggered longitudinally relative to each other for wide spread gripping without requiring safety elements of more than one length. Preferably the ribs of the transverse rows terminate short of the margins of the sole, as illustrated.

The heel of the shoe illustrated in Figures or i and 9 respectively. These two members are molded by inserting into the proper grooves in the mold the required numbers of safety coils 8 and then filling the mold with the synthetic or natural rubber material of which the sole is to be formed. During the molding operation the rubber flows throughout the mold and embeds the safety coils S-in their respective ribs.

After the molding process is completed each of the ribs 5 and i has the appearance of the fragmentary ribs shown in Figures IV, VII and X. In these ribs the safety coils 8 are embedded in the resilient rubber-like material of which the rib is formed.

After the shoes equipped with the safety soles embodying the invention have been worn for .i

but a short time the thin layer of rubber which may cover the bottom surface of the coils 8 wears away as is illustrated in Figures V, VIII and XI exposing certain portions it of the turns of the coil s at the flattened part H of the ribs 5 and '5. These short strips of metal do not protrude beyond the surface of the rib i but, immediately upon th application of excessive pressure to the shoe as, for example, when the wearer starts to slip, the rubber i retracts exposing the sharp edges of the portions 88 of the coil 3.

It should be noted that the coils 8 are not bonded to the rubber of which the ribs I and 5 are composed, it being desired that upon excessive pressure the rubber should retract ex- 4 posing the sharp edges of the metal which then grip the surface on which the wearer is walking.

In Figures VI, IX and XII one of the ribs 1 is shown in the condition which it assumes upon further wear of a shoe equipped with a safety sole embodying the invention. In these figures it is seen that the lowermost connecting portions ii) of the coil 8 have been worn away leaving exposed the ends l2 of individual coils 53 of the safety coil 8. At this condition of the shoe sole the action of the resilient rubber of which the ribs 1 are composed with respect to the ends l2 or" the individual coils of the safety element 8 is highly analogous to that of the claws of a cat.

In a shoe sole embodying the invention which may have, for example, as many as a dozen and a half or two dozen of the safety elements s embedded in its raised ribs, there will be many dozens of protruding points !2 applied sharply and suddenly to the surface on which the wearer is walking whenever excessive pressure is ap plied to the shoe sole, as upon a sudden slipping of the wearer.

Wearers of safety soles embodying the invention have found that it is entirely safe to walk on highly pitched surfaces covered with glazed ice, the individual ends 62 of the coils acting as claws to hold the wearer in an upright position and prevent him from slipping.

While it would be possible to produce a safety sole having ribs in which coils of wire of helical form were embedded and while such a shoe sole would provide the same features of safety gripping upon slight wear of the sole, if the coils 3 were formed in a helical shape they would immediately unscrew or wind their way out of the rubber ribs 5 and "i. This objection could be overcome by bonding the metal forming the coils 8 to the rubber forming the ribs 5 and l, but if the two were bonded together then the rubber in the ribs 5 and "i would not retract away from around the portions is or ends 52 of the coils 3 when excessive pressure was applied. These two shortcomings, i. e., the unwinding of the coil and the necessity for bonding the metal and rubber together both are overcome by the use of safety coils it designed in accordance with Figure XIII of the drawings.

The safety coil 8 as illustrated in Figures XIII and XIV of the drawings is manufactured by first forming a straight piece of wire into a sinusoidal form. This may be most easil accomplished by passing it through a pair of intermeshed forming gears to give the wire a wave of definite size and shape. After the wire has been formed into a sinusoidal shape it is then wrapped around a rotating axially moving mandrel to form it into the shape shown in Figures XIII and The mandrel employed is of a diameter the same as the finished interior diameter of a coil 8.

The irregularity of the shape of a coil 8 formed in the manner described prevents it from working its way out of theresilient rubber material. Because the coil does not work its way out of the rubber material it is therefore unnecessary to bond it to the rubber material and consequently the-retraction of the rubber material under excessive pressure, which is necessary to expose either the flattened portions it of the coils S3 or the ends 12 of individual loops is of the coils t, is acomplished without risk of loss of the coiled wire.

i What I claim is:

1. In a sole adapted for attachment to footwear, a flexible rubber tread'provided with a plurality of longitudinally spaced, generally transversely extending ribs, metal coils imbedded in said ribs, said coils being of equal length to one another and of substantially less length than the width of the widest portion of the sole, and one coil being transversely staggered with respect to the longitudinally spaced adjacent coils there being ribbed portions which are located between coils of adjacent ribs, which portions are devoid of a coil.

2. In a sole adapted for attachment to footwear, a flexible rubber tread provided with a plurality of longitudinally spaced generally transversely extending rows of ribs, the rows being of varying length depending upon the width of the particular portion of th sole in which the row is located, a majority of said rows comprising a relatively long rib portion of substantially less length than the maximum width of the sole and a shorter rib, the relatively long rib portions of the several rows being of substantially the same length and the shorter rib portions being of varying length, and metal coils imbedded in the relatively long rib portions only, said coils being of equal length to each other, said shorter rib portions being located between the coils in longer rib portions.

3. In a sole adapted for attachment to footwear, a flexible rubber tread provided with a plurality of spaced rows of ribs, the rows being of varying length depending upon the particular portion of the sole in which the row is located so as to extend substantially the length of said portion, a metal coil imbedded in a rib portion of a majority of the rows, said coils beingof equal length to each other and the coil in one row being staggered in respect to the coils in adjacent rows, there being a portion of a majority of the rows located between coils of adjacent rows which is devoid of a coil.

4. In a sole adapted for attachment to footwear, a flexible rubber tread having a ribbed portion which is provided with a plurality of spaced ribs which are of substantially equal length to one another and which are of substantially less length than the maximum width of said sole, metal coils embedded in said ribs with one coil in a rib, said coils being of substantially equal length to each other, and there being other ribs of less length than said coils and of less length than said first mentioned ribs interspersed therebetween, said last mentioned ribs being devoid of coils, those ribs which have coils being so arranged as to provide for coil engagement with a surface throughout the width of the ribbed portion of the sole when the sole is moved in a longitudinal direction on said surface.

References Gited in the file of this patent UNITED STATES PATENTS Number Name Date D. 108,623 Kavenagh Mar. 1, 1938 922,555 Baddock May 25, 1909 1,199,902 Kempshall Oct. 3, 1916 2,557,946 Crooker June 26, 1951 FOREIGN PATENTS Number Country Date 4,642/97 Great Britain Sept. 18, 1897 5,279/84 Great Britain Mar. 22, 1884 513,141 France Feb. 8, 1921 722,098 France Mar. 11, 1932 OTHER REFERENCES Popular Mechanics, March 1940, page 416. 

